When one develops the condition of cataracts, the usually clear natural lens of the eye becomes partially or completely opaque so that the passage of light to the retina is partially or totally inhibited. The problems of cataracts can be substantially alleviated by removing the cataract lens and replacing it with a man-made implant.
There is a large variety of possible intraocular lens implants available for use in cataract surgery. There is also a variety of methods for inserting the lens into the eye. Many medical practitioners have expressed a desire to have a tool which would hold the lens during insertion and permit the lens to be inserted through a small incision. A small incision is an incision smaller than the minimum dimension of the outer envelope of the lens when it is in a completely relaxed condition.
Certain intraocular lenses are made of flexible materials like silicone or hydrogel. Such lenses may be folded into a very small shape and inserted through a very small incision. Once the lens is inside the eye it is possible to have the lens relax and expand to its original shape. Certain medical practitioners believe that the smaller the incision through which the intraocular lens implant is introduced into the eye the better. Smaller incisions are believed to create less trauma for the patient with fewer sutures required and allow the healing process to proceed more quickly. Many procedures which use relatively large incisions, which are larger than the minimum dimension of the envelope of the lens, have been used for many years with satisfactory results. Some believe the smaller incision to provide further and additional benefits, but this is not to suggest that the use of a larger incision is in any way unsatisfactory.
In order to insert a lens through a small incision, it is necessary to reduce the size of the envelope of the lens. It would be convenient to have a tool which can readily reduce the size of the lens for insertion through a small incision and then easily release the lens once it is inside the eye.
It would also be desirable to have a reusable portion on the lens insertion tool which could be sterilized and used on a variety of patients and a disposable portion which would come in contact with the lens and with the eye of the patient.
Throughout this application the word distal is used to describe that portion of the instrument which extends away from the user during use whereas the word proximal is used to describe that portion of the instrument that extends toward the user during use.
Throughout this application the word cylindrical is used to describe the shape of various parts. The word cylindrical is not meant to be limited to a right circular cylinder but can include any shape which can be generated by moving a line parallel to itself about an axis and could include a circular, oval, square, rectangular or a polyhedronal cross section.